Flow regulating device



Jan. 26, 1965 w. c. LING 3,167,299

FLOW REGULATING DEVICE Filed Jan. 5. 1961 Inventor WILFRED C. LING United States Patent Ofitice 3,167,299 Patented Jan. 26, 1965 3,167,299 FLOW REGULATING DEVICE Wilfred C. Ling, Waukegan, Ill., assignor to Abbott Laboratories, North Chicago, 111., a corporation of Illinois Filed Jan. 5, 1961, Ser. No. 80,832 3 Claims. (Cl. 251-8) This invention relates to an adjustable tubing clamp for, regulating the flow through flexible tubing. More particularly, the present invention relates to an improved tubingclamp which serves to compensate for the undesiredcold flow properties commonly associated with plastic tubing.

' In the administration of parenteral solutions, it is common' practice to employ a length of flexible tubing for conveying the solution from a container to the recipient. The flow rate of such solutions is measured in such minute quantities as drops per minute. Some means, therefore, must be provided to accurately regulate the flow of the parenteral solution through the tubing. The preferred flexible tubing used in administering parenteral solutions is composed of a polyvinylchloride plastic material. This particular material is well suited for its purpose because it has the ability to withstand various types ofsterilization techniques. It is also relatively inert and contamination is kept to a minimum. One of the serious disadvantages of polyvinylchloride, however is that it tends to flow once it is placed under an appreciable stress. This is what is known in the trade as cold flow. It is a common complaint that when polyvinylchloride tubing is partially pinched to a designated degree so that a precise amount of solution is flowing therethrough, after a very short period of time, the rate of flow will continue to decline. Consequently, the clamp must be continually adjusted in order to maintain a steady rate of administration. The steady decline is attributed to the cold flow properties of the polyvinylchloride tubing wherein the tubing tends to constrict itself in such a manner that the passage therein becomes smaller and smaller.

I Various types of tubing clamps have been employed in an attempt to constrict flexible tubing in such a manner that the cold flow properties of the flexible tubing such as polyvinylchloride is lessened as much aspossible.

It is an object of the present invention to provide a tubing clamp for flexible tubing which will precisely regulate theflow of liquid theret'hrough.

It is also an object of the present invention to provide 'a tubing'c lamp'which can be minutely adjusted so as to maintain a constant rate of flow through plastic tubing having cold flow tendencies. I V q It is a further object of this invention to provide a flexible tubing clamp which accomplishes the foregoing objects while reducing the amount of cold flow of the tubing'to a minimum.

The foregoing and other objects of the present invention will be readily appreciated by reference to the following detailed description when considered in conjunction with the accompanying illustrative drawing of a preferred embodiment of the present invention wherein:

FIGURE 1 is a perspective view of the improved clamp operatively engaging and constricting a length of flexible tubing;

FIGURE 2 is a side elevational view, with a portion broken away, of the clamp of FIGURE 1 rotated at approximately 90 and with the flexible tubing removed therefrom;

FIGURE 3 is a view in vertical section of the clamp of FIGURE 1; and

FIGURE 4 is a top plan view of the clamp of FIG- In the illustrative drawing, a flexible tubing clamp designated generally at 10 comprises a substantially U- shaped clamp body 11 having axially extending leg portions 12 and 13 for accommodating a length of flexible plastic tubing 14 therethrough. The tubing 14 is, in this instance, composed of a polyvinylchloride plastic material for better illustrating the constricting mechanism of the tubing clamp 10 and the problems concerned with such tubing. A constricting bar 16, which comprises a thin metal axially extending plate, is movably and axially disposed in a bridge portion 17 of the clamp body 11 between the leg portions 12 and 13 for intersection with the tubing 14. A non-traveling nut 19 is mounted on the bridge portion 17. Internal threads 20 are provided in the nut 19 for threadable reception by an externally threaded portion 22 of the constricting bar 16.

Referring specifically to FIGURE 2, it will be seen that the constricting bar 16 has an internal gradually tapering tubing constricting slot 23 with a substantially V-shaped configuration. The gradually tapering tubing constricting slot 23 has a somewhat semi-circular opening portion 24 at one end and tapers inwardly in the direction opposite the opening to form a more constricted opening portion 25. The semi-circular opening portion 24 is of sufficient dimension to accommodate the tubing 14 without constriction, while the constricted opening portion 25 is of a dimension to completely compress the tubing 14 so that the flow of liquid therethrough is rendered impossible. The gradual taper of the slot 23 between the opening 24 and the constricted portion 25 provides for incremental constriction and consequently incremental selection of the rate of flow of liquid through tubing 14. As best illustrated in FIGURE 3, the constricting bar 16 extends transversely through the bridge portion 17 and is guided therein by an axial guide slot 27. The constricting bar 16 extends from the bridge portion 17 in a parallel manner With respect to the leg portions 12 and 13 and equidistant between them. The tubing 14 is centrally disposed through the clamp body 11 by passageways 28 and 29 of the leg portions 12 and 13, respectively. The constricting bar 16 is centered in the bridge portion 17 of the clamp body 11 in a transverse manner with respect to. the tubing 14 so that the tubing 14 when held by the transversepassage-ways 28 and 29, is'aligned for constriction by the slot 23. Reference is made to'FIGURE 2 which specifically shows the transverse alignment of the slot 23 with the passageway 29 and the passageway 28. v

j The non-traveling nut 19 is retained on the clamp body 11 by means of an inwardly projecting flange 31 and a circumferential groove 32in the clamp body 11, whereby the nut 19 is locked onto the clamp body 11. The'nut 19 has a knurled surface 3J3 for easy grasping. For the same reason, it is designed to extend a short distance beyond the walls of the clamp body 11 between the corners thereof as best shown in FIGURE 4. While the overall configuration of the clamp body'11 is U-shaped, the top is rectangular. The constricting bar 16 is relatively narrow in construction and is disposed within the confines of the circular, non-traveling nut 19. It will be noted that constricting bar 16 is spaced a short distance from both arm portions 12 and 13. The distance from the constricting bar 16 to the arm portions 12 and 13 is approximately /5. The total distance between the innerfaces of legs 12 and 13 is approximately These dimensions are found to work well with the tubing 14 having an internal diameter of .120" and an outside diameter of .170. Its purpose is to prevent the tubing from constricting itself in the passageways when it is constricted by the slot 23. If the constricting bar 16 were to abut against either of the leg portions 12 or 13 when the tubing 14 is constricted by the slot 23, the stress which' is exerted on the tbing would tend, in .to I

of the'confinement of the tubing by'the Walls of thecl amp Ibody with the result that the same"cold flow problemv associated with'slot 2 3 and-the tubing would'occur in the "adjacent'passagewaysc B'assag'eways 28 and'29[are"of a const'rict t'he tub ing'in the adjacent passageways because I -1 A: ubinsvc a hn or gu t ng flow hrou h, avian il of flexiblettubing comprisingz a clamp body having a pair of axially extending arm portions, a constricting bar slightly smaller dimension than the tubing '14 so -that a V slight frictional resistance occurs. Consequently, the tub.-

ing clamp 10 can be moved along 'thetubing 14 to any 7 pre-selected point and will remain at} that I point even though no constriction is' caused by constricting bar 16.

To operate the tubing clampj 10, thenut 19'is turned to align semi-circular opening 24, in the slot 23 with the v passageWaysZS and 29; Alength of flexible tubing 14 which is partof the commonintravenous administration set is passed through theipassageways 28 and 29 and consequently throughithe semi-circular opening portion 24. When it'is desired to restrict or stopJthe flow of liquid through theftubing1fl14, the non-travelingnut 19 is. ro--' tated in a' direction] to, move'the more constricted opentially constricted by. the. slot 23 and some liquid is. allowed to flow 'through'thettubing.

I As previously explained, plastic tubing, when placed under stress v tends to fflow and constrict by itself, there.-

a by, reducing the flowage through the tubing To coma pensate for this self-constriction, the nut 19 can be 'rotated slightly to move. the constricting bar 16 incremenv tally so that the tubing '14" is positioned ina less eon-n 1 stricted portion of the slot 23.

I It willthus be apparentlthat applicanthas previded tubing clamp. for flexible. plastic tubing having means a for precise and accurate adjustment to compensate'forjthe cold flow properties of plastict ubing, The adjustment means in carrying out its function also avoids creating H further'stress a'nd consequently, additional fcold flow.

Even where cold flow is not a problem in'tubing, the tubing clamp provides for, incremental regulation of the flo'wage rate or the parenteral: solution. The present tubing clamp prevents any accidental; or unintentional overposed'in general transverse alignment with said gradually constriction or overrelease of the tubing during adjustment.- a a I constricting bar 16, in this instance, is composed of aluminum, but other non-corrodiblemetals can -be*emmounted in said .clamp'body for axial movement between said axially extending arm portions, said constricting bar having an axially extending gradually tapering tubing constricting-slot, a passageway, in each, arm portion disposed in general transverse alignmentuw'ith each other and disposed in general transverse alignment with said gradually tapering tubingconstricting slot, said aligned passageways and gradually'tapering tubing con- 'stricting slot being adaptedto receive a length of flexible.

tubing, said; arm 1 portions each; being spaced a suflicient distance from said' constricting bar to substantially vent constriction of thetubing in said passagewaysaiid means engageable with said; clamp body and ,said con stricting-bar for actuating said" constricting bar axially; 2. Atubing clamp for regulatingflowthr'ough alength o-ffl'exible tubing, comprisingg .a'clampbody having [a pair of axially extending arm port-ions,a constrictingjbar mounted in sai d clamp body for axial movement between said axially extending arm portions; said constricting barhaying an axially" extendingjjigr'adually tapering tubing constricting :slotfa' passageway ,in'each' arm portion dis-. posed in general transverse alignment with each other and disposed in general transverse alignment with said gradually tapering tubing constricting slot, said aligned passageways and graduallytapering tubing constricting slot being adapted to receive a length of flexible tubing; said armportions each.being spaced a sufiicienttdistance from :said constricting bar to substantially rpreventiconstriction of the tubing in said passageways, ,said constrictingtb'ar having a threadedlportion, a nut threadably re, ceived by said constricting bar, and means for locking sa'idnut against axialfmovement, T

' 3'. A tubing clampQfor regulating flow through a length of flexible tubing, comprising: a: clamp bodyfhaving a, pair of axially extending arm portions, a constricting bar mounted in said clamp body foraxial movement between .said axially extending arm portions; said constrictin'gbar having an axially extending gradually taperingtubingzcon strictingslot," a passageway in each arm'portion disposed ingeneral transverse alignment with'each other and distaperingttubing constricting slot, said aligned passageways and gradually taperinggtub inga constricting slot being adaptedto receive a lengthofflexi-ble'tubingtsaid con-" ployed. The clamp'body ll and non-traveling nut 19 a-r'e' composed of polyethylene, howevenvother semi-rigidand rigid plastic materials such aspolyP ifipylen'e, polyamides,

polystyrene; 'methylmethacrylate, and fotheii acrylate poly-9 of the features disclosed, 0,1 equivalents thereof. atfl" present advised Withresp'ect to thejpr'e-sent scopegof my I t inventioml claimttlieifollowingtsubjectmatten strictingbar. having. aithreaded portion, a nut threadably 'receive'dby said constricting bar, andmeans for locking said-nut againstiaxial movement, said lockingv meansin p p a p D V t cludin means for snapping said nut into-said clam bod mrscommonlyknow lasImp exbcan also be: utilized;". H .1 I v lieferehceslCiteth i theilf le. ema ate UNITEDISTATES PATENTS.

1,43 ,353 Allen, Dec: 12, 1922 1,774,152? ,Anderson Au .;2 ,y1930 "2,250,117 Noblitt July 22,1941

858 18 8" Reamer an-5s June ,1 59 

1. A TUBING CLAMP FOR REGULATING FLOW THROUGH A LENGTH OF FLEXIBLE TUBING, COMPRISING; A CLAMP BODY HAVING A PAIR OF AXIALLY EXTENDING ARM PORTIONS, A CONSTRICTING BAR MOUNTED IN SAID CLAMP BODY FOR AXIAL MOVEMENT BETWEEN SAID AXIALLY EXTENDING ARM PORTIONS, SAID CONSTRICTING BAR HAVING AN AXIALLY EXTENDING GRADUALLY TAPERING TUBING CONSTRICTING SLOT, A PASSAGEWAY IN EACH ARM PORTION DISPOSED IN GENERAL TRANSVERSE ALIGNMENT WITH EACH OTHER AND DISPOSED IN GENERAL TRANSVERSE ALIGNMENT WITH SAID GRADUALLY TAPERING TUBING CONSTRICTING SLOT, SAID ALIGNED PASSAGEWAYS AND GRADUALLY TAPERING TUBING CONSTRICTING SLOT BEING ADAPTED TO RECEIVE A LENGTH OF FLEXIBLE TUBING, SAID ARM PORTIONS EACH BEING SPACED A SUFFICIENT DISTANCE FROM SAID CONSTRICTING BAR TO SUBSTANTIALLY PREVENT CONSTRICTION OF THE TUBING IN SAID PASSAGEWAYS AND MEANS ENGAGEABLE WITH SAID CLAMP BODY AND SAID CONSTRICTING BAR FOR ACTUATING SAID CONSTRICTING BAR AXIALLY. 